Synchronous motor



2 Sheets-Sheetl l of JANZEN SYNCHRONOUS MOTOR Filed Jan. 13, 1931 Oct. l5, 1935.

O. JANZEN VSYNQHRONOUS MOTOR Flled Jan 13, 1951 Oct. 15, 1935.

Patented ct.' 1.5, '1935 unirsi) STATES A15.1.*1aNT oFFicE l aoiasze' SYNCHRONOUS MOTOR l Otto Janzenperlin, Germany Application January 1s, 1931, serial No. 508,538

In Germany January 17, 1930 i claim. (ci. nazie) The invention relates to a synchronous motor which differs from the motors of the types already known by its simple construction, by the possi bility of a simple and cheap manufacture and by 5 its novel electromagnetic working. Particularly the way of its magnetization and the possibility of making it of cast iron lead toa very noiseless A working of this motor so that the latter is-eirtremely suitable for driving talking machines. l0 For the excitation of both the stator and the rotor one single coil is used which is concentric with the 'motor shaft. On account ofthe novel shape of the stator and the rotor` this coil is fully enclosed by these items. As the pole teeth of the stator and the rotor are uniformly distributed over the whole periphery, also the magnetic field radiates radially in all directions so that the iield resulting between stator andy rotor is absolutely homogeneous in contrast to that of the general arrangement already well-known -where one or several magnetic axes are made use of. The magnetic eld being homogeneously distributed at the same time over all poles aiords not only the advantage that all poles are simultaneously uti- 245 lized for the work to be accomplished but-also that the poles are all subject to the same radial magnetic attraction towards the center so that oscillations are not liable to arise in the magnetic axes of stator and rotor and thus the noise is reduced to a minimum.

A new departure also consists in the electromagnetic arrangement of the poles inasmuch as all poles on the periphery of the stator are of the same sign the same as all poles on the periphery of the rotor'these -slgns being however opposite in either series of poles.-

A new departure further; consists in the fact l 'that the geometric arrangement of the stator and the rotor is absolutely identical, this geometric 40 similarity just resulting in the homogeneous etic eld referred to as any cross section of the motor through the center line presents the same picture.v A motor vconstructed in accordance with the present invention is thus given an 4'5 'excess vof power which absolutely assures the.

perfect running ofthe record even it the range of amplitudes of the sound curve is rather extended. g

A synchronous motor built on 4these general 50' lines can be very simple and compact. [In this case the stator is to be made in two halves in the contact plane of which is arranged the exciting coil which vis concentric with thev shaft centerline of the plate and enclosed by the housing. .In the said plane either half of the stator isprcvided with a ange square with the plate axis. Both flanges lead the magnetic flux around the coil andfurther contain the means for fastening both stator halves to each other.

Another advantage of the object of the invenconstructions,

.- Fig. 5 a cross sectiony on line C-D of Fig. 5,

Fig. 7 a section on line A-B of Figa, 20

Fig. 8 a top plan view of a motor,

Fig. 9 a section through the motor shown Fig. 8, i

The forms of execution corresponding to Figs. 1 'and 2 are mainly suited for the obtention of a 25 lat type such as required, that is, for talkingmachine'motors whereas Fig. 3 shows a type which is more compact in a lateral direction. The figures referred to clearly show that a single coil- Sp is arranged concentrically in re- 30!- spect to the motor shaft A. The coil Sp is fully enclosed by the rotor L and thestator St. The magnetic circuit is closed over two air-gaps one of which is.outside and the other within the coil. Fig. 4 is a more detailed representation 35 of a motor corresponding -to the diagram Fig. 1-

the poles off which are arranged at the outside air-gap only as the section Fig. 7 clearly shows. The instance of execution represented by Fig. 5 essentially corresponds to the diagram Fig. 1 40 apart from` the fact that the poles are arranged both at the inside and outside air-gaps. Thus, in this instance of execution double the number of poles will be effective as compared with Fig.

4 but, of course, the number of revolutions is de- 45 termined only by the number of poles arranged on one add the same circle. Fig. 6 is a 'sectionot the instance of execution shown by Fig. 5.l Figs.

8 and 9,-show a. motor arranged according tothediagram Fig. 3 but with outside and inside air- 50 j gaps located at different levels. Also 4in this case, similarly to the' arrangements shown by Figs. 4 and '1, the polesare arrangedat the outside airsap only.

1n au figures it has 'been clearly marked nowv at the lines of force cross the air-gaps; moreover Fig. 9 shows the path of the same by means of dotted lines. In all cases vthe stator and the rotor are preferably made of cast iron.

When the rotor is moving, it is accelerated by the magnetic pull until the teeth of the stator and the rotor respectively are standing opposite each other.` In this instant magnetic -forces are developed which tend to keep the rotor in this sym# metrical position. 1f the current andthus the its maximum whereas the braking forces are determined by the weak currents developed in the neighbourhood of the zero value.

What I claim as my invention and desire to secure by Letters Patent, is-

In a slow speed synchronous motor of the 'character described iorvdirect driving purposes, in

combination a solid stator provided with teeth.

a solid roto;` having lthe same number of teeth and similar geometrical configuration relative t'o the magnetic ileld'as the stator, an exciting coil adapted for the simultaneous excitation of stator and rotor, an alternating current source 4for exciting the said coil, the solid stator and solid ro- .Y

tor consisting of cast iron'which forms a path of the lines of force having a high magnetic remanence for the magnetic ux.

OTTO JANZEN. 

